It is clear that Shylock kept Jessica effectively locked up. Note how he tells her in Act II scene 5 to "fast bind, fast bind" the house in his absence. Clearly, life with Shylock could not be pleasant bearing in mind his character and nature. Jessica herself describes life with her father as a "hell" in Act II scene 3 and Launcelot is quick to find an alternative employer. However, we see that in Act II scene 6 she leaves her father's house to elope with her love, Lorenzo. She makes clear her plan in Act II scene 3 when she says:
If thou keep promise, I shall end this strife,
Become a Christian and thy loving wife.
Interestingly, Jessica's robbing of her father's wealth seems to find its mirror in the wealth that Bassanio gains when he "wins" Portia. Marriage is shown to not just be an affair of the heart in this play: it is also a business deal as well, with a woman bringing wealth to the husband. Certainly Bassanio, in spite of all his comments of love, would not have been so interested in Portia if she was not "richly left" by her father. Lorenzo profits greatly because of his union with Jessica, and Shakespeare, by having Jessica rob her father, makes the mercantile element of marriage clear in this play that is so much about money.